Capsule inspection and separation



July 9, 1963 M. DUDYAK 3,097,161

CAPSULE INSPECTION AND SEPARATION Filed June 23, 1961 BY W MA 7/Patented July 9, 1963 3,097,161 CAPSULE INSPECTION AND SEPARATIQNMichael Dudyak, Spring Valley, N.Y., assignor t0 American CyanamidCompany, New York, N.Y., a corporation of Maine Filed June 23, 1961,Ser. No. 119,104 3 Claims. (61. 209-42) This invention relates to aprocess and apparatus for inspecting capsules and separatingslack-filled capsules from properly filled capsules economically andefficiently by using an air jet system.

In manufacturing capsules, particularly capsules for medicinal purposes,it is necessary that each capsule contain the proper amount of materialsuch as medicament. With some capsules such as those containing vitaminswhich are used over a long period, primarily for preventive rather thanfor therapeutic purposes, a single slack filled capsule is not tooserious. With capsules containing antibiotics or analgesics and manyother therapeutic agents, the contents of a single capsule are reliedupon to do a particular job at a particular time, and it is thereforenecessary that each capsule contain the desired quantity of medicine.

Any filling operation for the filling of capsules can go wrong, eventhough highly reliable apparatus and processes are used so that thenumber of defects is a small fraction of 1%. Nonetheless, it isnecessary or desirable that the defective capsules, no matter how smalltheir percentage, be selected and rejected. in many instances, thecapsules are opaque so that visual inspection does not give a reliableanswer. it is usually desirable that a visual inspection be used, andadditionally some other method of eliminating defectively filledcapsules. Medical capsules are usually either hard-shell capsules, inwhich two pre-formed parts of the capsule are telescoped together tocontain the filled material, or softshell capsules which are formed fromstrips of soft plastic such as gelatin, with water and plasticizers. Thewall thicknesses are uniform, hence any variation in weight isindicative of an improperly filled capsule. The size of capsule isusually chosen so that it is impossible to overfill the capsule becauseit is desired that the maXimum contents be placed in the capsule so thatthe capsule is as small and easily swallowed as possible. The individualweighing of the filled capsules on a sufficiently sensitive scale orbalance would give an adequate check; but individual weighing is tooexpensive and time-consuming to be used in production quantities, ifother processes can be devised.

One method of filling capsules is set forth in United States Patent No.2,775,080, Method of Forming Powderand-Liquid Filled Capsules, F. E.Stirn and A. S. Taylor, December 25, 195.6. FTGURE 16 of this patentshows an air conveyor system for removing capsules from the fillingmachines.

One method of separating improperly filled capsules, that is,slack-filled capsules, is described in United States Patent No.2,727,833, Capsule Finishing Process, E. C. You and F. E. Stirn,December 20, 1955. This patent describes a method of treating thecapsules with a washing and coating composition and uses a solution forwashing and coating of such specific gravity that the properly filledcapsules sink and slack-filled capsules float, thus permitting theskimming oil of slack-filled capsules. Such a process is limited by thespecific gravity of available solutions and leaves the capsules wet sothat they must be dried. Whereas this is highly advantageous as acombined process where a coating is desired, at times a coating step isnot necessary or desired, and it is hence not desirable to wet thecapsules, as is necessary for such a sink or float process.Additionally, a drying step is required, and at times the coatingliquids present fire or health hazards.

The present invention provides a method of rapidly separatingslack-filled capsules and other defective capsules by passing thecapsules to be inspected down an inspection belt. At an inspectionstation on this belt, the capsules are brightly illuminated andinspectors pick out and reject capsules which appear to be questionableor defective.

The capsules are then deflected from the inspection belt down a capsulechute down which the capsules slide, preferably as a single thicknesslayer. An air jet underneath the chute blows a current of air upwardlyfrom the floor of the chute, or at least slightly in the direction ofcapsule travel, so that each capsule in turn is subjected to theaerodynamic influence of an air blast. The strength of the air blast ischosen such that the prop erly filled capsules follow one path, whileslack-filled capsules, being lighter, are picked up by the air from theair blast and caused to follow a separate path. This separate path leadsto a slack-filled capsule waste basket. The identical apparatus may beused for capsules having a wide variation in apparent density bychanging the force of the air blast. The air blast can be chosen of suchstrength that only capsules of at least a specific weight will passwithout rejection, thus giving an extremely rapid and very inexpensivemethod of inspection.

The air jet may consist of a single narrow, comparatively long jet or aplurality of single jets; but conveniently is at least one row andpreferably a double row of individual air jets spaced such that nocapsules can escape the influence of the air blast from one or more suchair jets as it passes down the chute, and at the same time by varyingthe air pressure capsules having different characteristics may bechecked on the same machine. It is easier to use air jets which aresmall, round, drilled holes preferably in two or more rows, althoughother shapes may be used. For most pharmaceutical capsules two rows ofjets, each consisting of a -inch hole, spaced fii-inch on centers andstaggered gives excellent results.

After the visual inspection and air blast, any dirt or impurities on thecapsules is picked up by the air blast and blown away and the inspectedcapsules may be passed to inspected capsule receivers as acceptableproduction, for counting, packaging or other procedures.

Whereas variation in the type and size of air jets and the size andproportion of chutes and slack-filled capsules dividers may be used, andvarious types of shields to prevent grossly underfilled capsules frombeing blown completely out of the apparatus, the accompanying drawingsshow one embodiment of the present invention; the full scope of theinvention being as set forth in the appended claims.

In the drawings:

FIGURE 1 is a pictorial view, in partial section, of the present capsuleinspector, showing the paths traversed by properly filled capsules andslack-filled capsules.

FIGURE 2 is a sectional view along line 22 of FIG- URE 1 showing a crosssection of the capsule inspection apparatus, and its method ofoperation.

Inasmuch as the suspending frame and the pulleys for the conveyor belt,etc., are conventional, such conventional items are not shown in thedrawings.

As shown in FIGURE 1, capsules 11 which may be either hardor soft-shell,pass along a conveyor belt or inspection belt 12. The capsules are puton the inspection belt in accordance with conventional practice, wherethe number on the belt is not greater than can be inspected by anoperator looking at the belt, and is such that the capsules are in asingle layer on the belt. A conventional drive is used. As the beltmoves along, the capsules are deflected from the inspection belt by adeflector 13, which is convenientlya strip of sheet metal at an angle of33 to 60 with the direction of travel of the inspection belt, andmountedslightly above so as not to drag on the inspection belt, whichpicks up the capsules and deflects them at an angle to the inspectionbelt and down the capsule chute M. The capsule chute is at such an anglethat the capsules slide readily down the chute by the influence ofgravity. An angle of about 20 to 45 is very convenient, although agreater or lesser angle may be useed. The capsule chute has a capsulechute floor 15, and capsule chute side guides 16. The side guides are atsuch a position as to control the path of the capsules, and keep them onthe chute floor.

Underneath the capsule chute floor is an air pressure box 17 which issupplied with the air under pressure from a suitable source, and whichair preferably passe 'through an air pressure reduction valve '18, acontrol valve 19, and into the air pressure box 17. An air pressuregauge 20 is used to indicate the pressure of air to aid in adjusting theair pressure to a desired value.

A plurality of air jets 21 are drilled in the floor of the capsulechute. These jets may be at approximately a right angle to the floor, ormay be inclined slightly in the direction of capsule travel so that theair blast from the air jets not only gives a lifting eifect -tothecapsules as they pass over air going to the air jets, but also cause thecapsules to develop an additional velocity component in the direction oftheir travel. Usually, the velocity of the capsules in sliding down thechute is suflicient that an additional directional componentto the airjets in the direction of motion is not necessary, although it sometimesaids inspeeding operations. Capsules which are not blown from thecapsule chute floor continue to slide down the capsule chute and into aninspected capsule receiver 22, which receives the capsules having aproper fill.

Above the bottom of the capsule chute is a divider 23. This divider isadjacent to'the' path ofthe air blast from the air jets, and extendsdown towardsthe floor of the capsule chute so that there is justsuflicient clearance between the divider and the floor of the chute forthe largest capsules which'are to be inspected on the apparatus. Thedivider extends between the sides of the capsule chute forming theslack-filled capsule trap 24.

Conveniently, the leading edge of the divider 25 is closely spaced fromthe air blast from the air jets so that slack-filled capsules cannotpass between the air blast and the leading edge of the divider. Theremainder of the divider is conveniently spaced a somewhat greaterdistance from, and is parallel to, the capsule chute floor, althoughthis parallelicity is not necessary. The top; of the slack-filledcapsule trap is conveniently a rectangular cover which extends from andbetween the capsule chute side guides and has a top parallel thereto. Ascreen 26 forms part of the slack-filled capsule traps to permit air toescape from the trap. 1n the slack-filled capsule trap, is a vane 27,which guides the slack-filled capsules towards a conveyor tube 28, whichleads to a slack-filled capsule waste basket 29. A conveying jet 30' isdirected along the vane and to the conveyor tube so as to pick up andcarry the'slack-filled capsules and convey them to the waste basket.This conveying jet is fed by a bleeder pipe 31 from the air line 32 tothe air pressure box 17.

Operation In operation, after visual inspection on the belt, thecapsules 11 are deflected from the inspection belt 12 and drop down thecapsule chute 14. As they slide down the chute, eachcapsule individuallyencounters the air blast 33 from the air jets 21. The properly filledcapsules 34 are'jcstled by the air blast, but are not lifted by the airblast, and continue to slide down the chute. The slackfilled capsules 35being lighter are lifted by the air blast and with the velocity fromsliding down the chute to give them forward motion, pass up and over thedivider 23 and into the slack-filled capsule trap 24 from which they areblown by the conveying jet 30 down the conveyor tube 28 into theslack-filled capsule waste basket 29.

It is to be understood that the, air pressure to be used can vary overfairly wide limits depending upon the size of the air jetandthelapparent density of the capsules which are being inspected] WithA -inch holes in two lines spaced Ai-inch on centers, an air pressure ofaround 8 to lbs. per square inch gives good results with mostpharmaceutical capsules. The air pressure in the air pressure box isgreat enough so that the air blast causes all of the capsules to bejostled and almost lifted to the divider 23. Then, capsules which areknown to be slackfilled, and perhaps identified by separate colormarkings, are tied with the properly filled capsules down the chute tosee if they are blown over the divider 23, and if not, the air blast isincreased until the slack-filled capsules are blown over the divider. Ininitial operation, it is frequently convenient to increase the pressureof air until the air blast picks up the few of the lighter filledcapsules or until some capsules are caused to be blown over the dividerinto the slack-filled capsule trap, and these capsules are weighed tosee if they are actually slack-filled or if the air blast issufficiently strong to lift properly filled capsules.

For each individual type of capsule, depending upon the aerodynamicqualities of the particular capsules, their size and their particularfill, the, air blast must be adjusted; but once the air blast isadjusted the same pressure reading on the air pressure gauge may be usedif the same type of capsule is run at a later date, rather thanrecalibrating. Similarly, the reading on the air pressure gauge showsthat the pressure is continuing to be maintained at proper value,although the air pressure reduction valve and the control valve settingsshould be sufficiently stable that no adjustments are required duringthe average production day.

It is preferred that the capsules be inspected visually as they comedown the belt 12 to be certain that the colors, sizes and shapes are inconformity with the desired inspection standards. Such inspection may beeither continuous or intermittent depending upon the quality of themachine forming the capsules. Frequently, with high grade machines,after the machines are once adjusted and working properly, no additionalinspection is required of the individual capsules for considerableperiods, and frequently merely a spot inspection by the machine openatoris sufiicient to insure quality control.

In many instances, with reliable encapsulation machines, slackfilledcapsules will be foundto exist only when the machine is being firststarted up, or when bridging occurs in the feed hoppers which feed thecontents to the encapsulation machines. If a powder filling is beingused, at times the powder can bridge in the feeding device to theencapsulation machine, resulting in a considerable number ofslack-filled capsules, or bridging may occur only for one or twocapsules in which case only a small number will be rejected.

As will be obvious to those skilled in the art, the machine as describedand illustrated may be modified somewhat and remain within the scope ofthe present invention which is defined by the appended claims.

I claim:

1. An apparatus for inspecting capsules and separating out ofslack-filled capsules which comprises: an endless inspection belt, meansfor continuously moving said belt on which is a single layer ofcapsules, an inclined capsule chute having at least one directional airjet in the capsuletraversing floor thereof, a deflector adjacent to saidbeltv to deflect said single layer of capsules from said belt to anddown said chute, an air pressure box under said chute, means forsupplying air under controlled pressure to said air pressure box, and byway of said box to said air jet in the floor of the capsule chute, aninspected capsule receiver below said chute to receive inspectedcapsules from said chute, a divider above said capsule chute spaced withjust suflicient clearance from the floor of the chute for a single layerof the largest capsules to be inspected to pass under said divider, andadjacent to the air blast from the air jet in the floor of said capsulechute, and spaced so closely to the air blast that a slack-filledcapsule cannot pass between the air blast and the divider, said dividerfoaming with the sides of the chute a slackfilled capsule trap, toreceive slack-filled capsules blown upwardly by said blast, a screenover the said divider, to prevent slack-filled capsules from being blownout into the apparatus, a slack-filled capsule basket, and an airconveyor to transfer slack-filled capsules from said slackfilled capsuletrap to said slack-filled capsule basket.

2. A11 apparatus for inspecting capsules and separating out ofslack-filled capsules which comprises: an endless inspection belt, meansfor continuously moving said belt on which is a single layer ofcapsules, an inclined capsule chute having at least one directional airjet in the capsule traversing floor thereof, a deflector adjacent tosaid belt to deflect said single layer of capsules from said belt to anddown said chute, an air pressure box under said chute, means forsupplying air under controlled pressure to said air pressure box, and byway of said box to said air jet in the floor of the capsule chute, aninspected capsule receiver below said chute to receive inspectedcapsules from said chute, and a divider above said capsule chute spacedwith just suificient clearance from the floor of the chute for a singlelayer of the largest capsules to be inspected to pass under saiddivider, and adjacent to the air blast from the air jet in the floor ofsaid capsule chute, and spaced so closely to the air blast that aslack-filled capsule cannot pass between the air blast and the divider,said divider forming a slack-filled capsule trap, to receiveslack-filled capsules blown upwardly by said blast.

3. A process for inspecting capsules and separating out slack-filledcapsules which comprises: passing a plurality of capsules in a singlelayer past a visual inspection station, visually inspecting, pickingout, and discarding capsules of defective appearance, passing thevisually inspected and passed capsules under the influence of gravitydown a sloped path in a single layer, blowing at least one air blastacross said sloped path, whereby each capsule is separately subjected tothe efiect of the air blast thus blowing the individual slack-filledcapsules to one fully defined path, separating out and discarding all ofthe same, and passing the heavier properly filled capsules down a secondpath, and separately receiving and storing the visually inspected andproperly filled capsules.

References Cited in the file of this patent UNITED STATES PATENTS1,003,138 Hupner Sept. 12, 1911 1,092,664 Parker Apr. 7, 1914 2,738,067Cook Mar. 13, 1956

1. AN APPARATUS FOR INSPECTING CAPSULES AND SEPARATING OUT OFSLACK-FILLED CAPSULES WHICH COMPRISES: AN ENDLESS INSPECTION BELT, MEANSFOR CONTINUOUSLY MOVING SAID BELT ON WHICH IS A SINGLE LAYER OFCAPSULES, AN INCLINED CAPSULE CHUTE HAVING AT LEAST ONE DIRECTIONAL AIRJET IN THE CAPSULE TRAVERSING FLOOR THEREOF, A DEFLECTOR ADJACENT TOSAID BELT TO DEFFLECT SAID SINGLE LAYER OF CAPSULES FROM SAID BELT TOAND DOWN SAID CHUTE, AN AIR PRESSURE BOX UNDER SAID CHUTE, MEANS FORSUPPLYING AIR UNDER CONTROLLED PRESSURE TO SAID AIR PRESSURE BOX, AND BYWAY OF SAID BOX TO SAID AIR JET IN THE FLOOR OF THE CAPSULE CHUTE, ANINSPECTED CAPSULE RECEIVER BELOW SAID SHUTE TO RECEIVE INSPECTEDCAPSULES FROM SAID CHUTE, A DIVIDER ABOVE SAID CAPSULE CHUTE SPACED WITHJUST SUFFICIENT CLEARANCE FROM THE FLOOR OF THE CHUTE FOR A SINGLE LAYEROF THE LARGEST CAPSULES TO BE INSPECTED TO PASS UNDER SAID DIVIDER, ANDADJACENT TO THE AIR LAST FROM THE AIR JET IN THE FLOOR OF SAID CAPSULECHUTE, AND SPACED SO CLOSELY TO THE AIR BLAST THAT A SLACK-FILLEDCAPSULE CANNOT PASS BETWEEN THE AIR BLAST AND THE DIVIDER, SAID DIVIDERFORMING WITH THE SIDES OF THE CHUTE A SLACKFILLED CAPSULE TRAP, TORECEIVE SLACK-FILLED CAPSULES BLOWN UPWARDLY BY SAID BLAST, A SCREENOVER THE SAID DIVIDER, TO PREVENT SLACK-FILLED CAPSULES FROM BEING BLOWNOUT INTO THE APPARATUS, A SLACK-FILLED CAPSULE BACKET, AND AN AIRCONVEYOR TO TRANSFER SLACK-FILLED CAPSULES FROM SAID SLACKFILLED CAPSULETRAP TO SAID SLACK-FILLED CAPSULE BASKET.